1. Field of the Invention
The present invention relates to an electrically powered gardening tool such as a power-operated hedge trimmer, an electrically powered grass shear and the like.
2. Description of the Prior Art
Disclosed in Japanese Patent Laid-open Publication No. 2005-295922 is a hedge trimmer of the type which includes a speed-reduction gear arranged to be rotated by operation of an electric motor, a crank-cam in the form of overlapped eccentric disk plates connected to a bottom surface of the speed-reduction gear by means of connecting pins for rotation therewith, and a pair of relatively reciprocating shear blades assembled with the eccentric disk plates. In operation of the hedge trimmer, the speed-reduction gear is driven by operation of the electric motor to rotate the eccentric disk plates of the crank-cam thereby to cause relatively reciprocating movement of the shear blades in engagement with the eccentric disk plates.
In the hedge trimmer, the connecting pins fixed to the crank-cam are detachably engaged within mounting holes formed in the speed-reduction gear to facilitate replacement of the shear blades. In such connecting structure of the crank-cam, clearance in the mounting holes causes slight movement of the connecting pins when the crank-cam is driven by rotation of the speed-reduction gear, resulting in the occurrence of contact noise of the connecting pins against the mounting holes.
To restrain the occurrence of contact noise, an elastic bushing may be interposed between the connecting pins and the mounting holes respectively. The busing is, however, damaged if the connecting pins of the crank-cam are applied with heavy load in a radial direction when hard tree branches or fine stones are caught in the shear blades during trimming operation.